Pharyngeal airway parameters in subjects with Class I malocclusion with different growth patterns

Objectives: (1) To test the null hypothesis that there are no significant difference in the pharyngeal airway in subjects with Class I malocclusion with different growth patterns. (2) To test the null hypothesis that there are no significant difference in dentofacial structure in subjects with Class I malocclusion with different growth patterns. Materials and Methods: Lateral cephalometric radiographs of 120 skeletally Class I were separated into three groups according to the SN-MP angle. Lateral cephalometric radiographs of 39 low angle, 45 high angle and 36 normal angle were examined. Group difference were analyzed with analysis of variance (ANOVA) and the Tukey test, at the P Results: For pharyngeal airway measurements statistically significant difference were found in pharyngeal airway length, and D5 (retroepiglottal) pharyngeal width. No statistically significant sagittal pharyngeal (D1-D5) parameters difference were determined between low angle and normal angle subjects. High angle subjects had lower sagittal pharyngeal D2 (retropalatal) and D5 (retroepiglottal) parameters than those with low and normal angle, additionally in high angle subjects had lower D1 (retropalatal) and D4 (retroglossal) parameters than those with normal angle subjects. According to ANOVA only 1 out of 9 dentofacial measurements showed not statistically significant difference among different growth patterns. Conclusion: The null hypothesis was rejected. Significant difference in pharyngeal airway measurements and dentofacial morphology of Class I subjects with different growth patterns were identified.